Field
Exemplary embodiments of the present invention relate to a touch device and a driving method thereof.
Discussion of the Background
Display devices such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an electrophoretic display may include a field generating electrode and an electro-optical active layer. The OLED display may include an organic emission layer as the electro-optical active layer. The field generating electrode may be connected to a switching element such as a thin-film transistor to receive a data signal, and the electro-optical active layer may convert the data signal into an optical signal to display an image. A display device may include a touch sensing function which may interact with a user in addition to an image displaying function. The touch sensing function may determine contact information such as whether an object contacts or approaches a screen and a contact position thereof by sensing a change in pressure, charges, light, and the like, which are applied onto the screen in the display device, when the user writes a text or draws a figure by contacting or approaching the screen with a finger or a touch pen.
The display device may receive an image signal based on the contact information to display an image. The touch sensing function may be implemented by a touch sensor. The touch sensor may be classified according to various types, such as a resistive type, a capacitive type, an electro-magnetic (EM) type, and an optical type. The capacitive type touch sensor may include a sensing condenser including sensing electrodes that may transfer a sensing signal and identify whether a touch exists or a touch location by sensing a change in charged capacitance or a change in the amount of charged charges of the sensing condenser, which may occur when a conductor such as a finger approaches the touch sensor. A display device incorporating the touch sensor has been recently researched.
A capacitance method includes a self capacitance method and a mutual capacitance method. In the self capacitance method, a capacitance is detected by applying a voltage to each of touch sensor electrodes and measuring a resulting voltage change. In the mutual capacitance method, a capacitance is detected by applying a voltage in an x-axis direction and detecting a voltage induced in a y-axis direction intersecting the x-axis direction.
The self capacitance method may have high sensitivity, and thus may provide a hovering function. However, due to an unexpected touch phenomenon, i.e., a ghost point may occur during a multi-touch, which may render performing the touch sensing operation difficult.
The mutual capacitance method may have lower sensitivity than the self capacitance method, but a multi-touch operation may be possible. However, since the mutual capacitance method has low sensitivity, a sensitive function such as hovering may be limited.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.